1. Field of the Invention
The present invention relates to a machine tool having a tool magazine and an automatic machine changer for changing a tool.
2. Description of the Related Art
Machine tools with an automatic tool changer (hereinafter also referred to as “ATC”) are disclosed in U.S. Pat. No. 4,729,159 and Japanese laid-open patent publication No. 59-227345, for example.
The ATC disclosed in U.S. Pat. No. 4,729,159 includes a feeder for gripping and feeding a tool, which travels outside the machining area of the machine tool. The machine tool disclosed in Japanese laid-open patent publication No. 59-227345 includes a tool magazine for storing tools therein. The magazine itself is movable, and the ATC changes tools between the magazine and a tool rest.
The ATC disclosed in U.S. Pat. No. 4,729,159 has a predetermined tool changing position with respect to a tool rest. For changing tools, the tool rest has to move from a machining position to the tool changing position. As the tool rest needs to move a long distance to the tool changing position, it is time-consuming to replace the tool on the tool rest with another tool. Accordingly the machining tool has a long non-machining time.
If the ATC disclosed in U.S. Pat. No. 4,729,159 is incorporated in an elongate machine tool having a horizontally long machining area, the tool rest has to move a correspondingly long distance to the tool changing position. Therefore, there has been a demand for a technology for greatly reducing the time required to change tools.
In the machine tool disclosed in Japanese laid-open patent publication No. 59-227345, a movable unit including a tool magazine is heavy and cannot move at a high speed. Furthermore, a mechanism for moving the tool magazine is large and complex, imposing limitations on the number of tools that can be stored in the tool magazine.
Other ATCs according to the related art include a tool feeder disposed between a tool magazine and a tool changer arm. Tools are changed between the tool magazine and the tool changer arm via the tool feeder. However, these ATCs with the tool feeder are structurally complex in their entirety.